1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
|
// run-pass
// To work around #46855
// compile-flags: -Z mir-opt-level=0
// Regression test for the inhabitedness of unions with uninhabited variants, issue #46845
use std::mem;
#[derive(Copy, Clone)]
enum Never { }
// A single uninhabited variant shouldn't make the whole union uninhabited.
union Foo {
a: u64,
_b: Never
}
// If all the variants are uninhabited, however, the union should be uninhabited.
// NOTE(#49298) the union being uninhabited shouldn't change its size.
union Bar {
_a: (Never, u64),
_b: (u64, Never)
}
fn main() {
assert_eq!(mem::size_of::<Foo>(), 8);
// See the note on `Bar`'s definition for why this isn't `0`.
assert_eq!(mem::size_of::<Bar>(), 8);
let f = [Foo { a: 42 }, Foo { a: 10 }];
println!("{}", unsafe { f[0].a });
assert_eq!(unsafe { f[1].a }, 10);
}
|
